The M4 corridor runs on cooling
Follow the M4 west out of London and you're soon in a stretch with a lot of cooling plant. The Slough Trading Estate mixes manufacturing, food production and warehousing. Reading, Bracknell and Maidenhead add business parks and corporate campuses running chilled-water systems. The Heathrow side of the patch, around Colnbrook and Poyle, is full of distribution sheds and cold storage, where evaporative condensers keep the refrigeration plant going.
Not every site here has an open tower. Plenty of newer buildings use dry coolers or adiabatic units, and those still need a Legionella risk assessment if they wet a surface or make spray. HSG274 Part 1 is clear that any unit able to produce aerosol needs its risk assessing. But open towers and evaporative condensers are still common on older office plant, process sites and food distribution, and they're the ones that need a full treatment programme.
Working around sites that can't stop
A cold store full of stock, a hospital plant floor or a production line can't just switch its cooling off for the day. We plan the work around that rather than asking you to. In practice that means:
- cleaning one cell or one tower at a time while the rest carries the load,
- agreeing dosing changes and setpoint adjustments with your engineers before we make them,
- taking samples at agreed times, with any escorts or permits booked ahead,
- writing reports in a format your auditors and maintenance team already use.
Site inductions take time on a first visit, so we build them into the start of the programme. Our article on taking over a site with cooling towers covers what to pin down early.
Water in the Thames Valley
Reading, Newbury and most of Maidenhead get their water from Thames Water. Slough is split, with Affinity Water serving parts of the town and its surroundings, and South East Water supplies parts of east Berkshire around Bracknell and Wokingham. Most of the area's water is hard, drawn from the Thames and the chalk. Your supplier's postcode checker will tell you which side of the line you're on.
For a busy tower, hardness has a real cost. On a hot day evaporation is heavy, and every litre that goes up the stack leaves its calcium behind. Set the bleed too tight and you waste water and chemical. Set it too loose and condenser tubes scale up on plant you can't easily take offline. Many larger sites here soften or otherwise pre-treat the make-up. If yours does, the softener needs watching too, because one missed regeneration sends hard water into a system tuned for soft.
Notification in Berkshire
Berkshire has no county council. It's six unitary councils: Slough, Reading, Wokingham, Bracknell Forest, Windsor and Maidenhead, and West Berkshire. Notification under the 1992 regulations goes to whichever one your site sits in, through your local council's environmental health team. On a campus with several towers, every one goes on the notice, and towers added during an expansion need notifying as well.
Getting there
From Chiswick we're on the M4 within minutes, which makes Slough and the Heathrow side easy to reach for routine visits, with Reading and Newbury further along the same road. Business parks usually have parking and ground-level plant yards. Secure logistics sites and hospitals are the opposite: everything goes through the gatehouse or estates office, so we agree vehicle details and visit slots in advance.